The present invention, in some embodiments thereof, relates to a flow regulator and, more particularly, but not exclusively, to a regulator for flow to an agricultural emitter that preserves a desired discharge under varying fluid inlet pressures.
With population increase and climate changes, water resources are becoming scarcer, forcing farmers and gardeners to save water and direct irrigation to a close vicinity of target plants. Such a directional irrigation is achieved by drip emitters, fed by an irrigation pipe of relatively high water pressure. Flow restrictors in the emitter reduce the water pressure such that the water emits an output inlet as drops, slowly irrigating soil near the emitter and a target plant.
U.S. Pat. No. 5,279,462 to Mehoudar and U.S. Pat. No. 4,209,133 to Mehoudar teaches a drip level irrigation emitter unit flow restrictor. A resiliently flexible membrane sealingly separates inlet and outlet control chambers. The membrane is displaceable with respect to the flow restrictor, such that inlet and outlet chambers respectively communicate with an inlet and an outlet of the flow restrictor. This is necessary in order to ensure that the predetermined pressure differential between the chambers is not unduly influenced by the magnitude of the inflow pressure.
U.S. Pat. No. 6,250,571 to Cohen discloses a drip irrigation emitter of the regulating labyrinth type with baffles facing an elastic membrane, the baffles having a concave configuration and also having notches of increasing depth from one end of the labyrinth flow path to the opposite end. Such a construction permits a continuous and gradual decrease to be produced in cross-sectional areas of the bypasses defined by the notches in response to an increase in the inlet pressure.
U.S. Pat. No. 4,623,094 to Smeyers teaches a dripper in which a flexible membrane has a frusto-conical part with a smooth outer surface facing a matching wall with a sinuous groove in a thickened portion of the wall.
U.S. Pat. No. 5,615,838 to Eckstein discloses dripper in which a resilient membrane is mounted in the valve chamber for closing an emitter inlet when the fluid pressure in the pipe is below a minimum pressure and for opening the emitter inlet when the fluid pressure in the pipe is above the minimum pressure. The membrane further flexes toward a generally flat inner wall housing second, third and fourth outlets at pressures greater than the minimum pressure. The second, third and fourth outlets and associated valve chamber are structured so that the fluid flow through the outlets is varied over respective ranges of pressures to produce, for higher pressures, fluid flow through more of a labyrinth.
Additional background art includes my U.S. Pat. Nos. 5,400,973 and 5,609,303, as well as in Eckstein et al U.S. Pat. No. 5,615,838.